扭动微动条件下含水气氛对氧化行为的影响

对7075铝合金/GCr15摩擦副在不同湿度条件下扭动微动的损伤行为、氧化行为进行了研究.建立了7075铝合金在不同湿度条件下的扭动微动运行工况微动图.采用SEM、XPS对不同湿度环境下的磨损机制、氧化行为及其影响因素进行了分析.结果表明:湿度对7075的扭动微动运行存在显著影响,随着湿度的增加,摩擦扭矩明显降低;部分滑移区的磨损发生在接触边缘,损伤轻微;混合区和滑移区发生强烈的塑性变形,损伤严重,其主要磨损机制是磨粒磨损和剥层;潮湿空气增加了界面滑移,反应生成的氧化磨屑起到了润滑剂的作用,减轻了磨损.

Oxidation Behavior in Different Humid Environments Induced by Torsional Fretting Wear

Torsional fretting wear of 7075 aluminium alloy flats against GCr15 bearing steel ball was investigated under various relative humidities (RH=10%, 60%, and90%).The normal loads (20 N, 50N and 100N) and torsional angular displacement amplitude (from 0.1o to 15o) were selected. The fretting running behaviors, wear mechanism, oxidative behaviors and the effect of various relative humidity were analyzed in detail, in combination with the micro-examinations of scanning electron microscope (SEM), and X-ray Photoelectron Spectroscopy (XPS). The experimental results revealed that the relative humidity significantly influenced the friction behaviors, wear damage and RCFM of torsional fretting. The wear mechanisms were mainly delamination and abrasive wear in three fretting regimes under different relative humidities. The results showed that slight damage was presented at the contact edges in partial slip regime, strong plastic deformation accompanied with the damages occurred in mixed fretting regime, and a debris layer was observed on the wear scars in slip regime. The friction torques decreased with the increasing RH. Humid air was beneficial to the slipping in the contact interface and the oxidation debris played as a lubricant in the fretting progress.